<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package		CodeIgniter
 * @author		ExpressionEngine Dev Team
 * @copyright	Copyright (c) 2008 - 2009, EllisLab, Inc.
 * @license		http://codeigniter.com/user_guide/license.html
 * @link		http://codeigniter.com
 * @since		Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Input Class
 *
 * Pre-processes global input data for security
 *
 * @package		CodeIgniter
 * @subpackage	Libraries
 * @category	Input
 * @author		ExpressionEngine Dev Team
 * @link		http://codeigniter.com/user_guide/libraries/input.html
 */
class CI_Input {
  var $use_xss_clean		= FALSE;
  var $xss_hash			= '';
  var $ip_address			= FALSE;
  var $user_agent			= FALSE;
  var $allow_get_array	= FALSE;

  /* never allowed, string replacement */
  var $never_allowed_str = array(
  'document.cookie'	=> '[removed]',
  'document.write'	=> '[removed]',
  '.parentNode'		=> '[removed]',
  '.innerHTML'		=> '[removed]',
  'window.location'	=> '[removed]',
  '-moz-binding'		=> '[removed]',
  '<!--'				=> '&lt;!--',
  '-->'				=> '--&gt;',
  '<![CDATA['			=> '&lt;![CDATA['
  );
									/* never allowed, regex replacement */
  var $never_allowed_regex = array(
  "javascript\s*:"			=> '[removed]',
  "expression\s*(\(|&\#40;)"	=> '[removed]', // CSS and IE
  "vbscript\s*:"				=> '[removed]', // IE, surprise!
  "Redirect\s+302"			=> '[removed]'
  );

  /**
   * Constructor
   *
   * Sets whether to globally enable the XSS processing
   * and whether to allow the $_GET array
   *
   * @access	public
   */
  function CI_Input() {
    log_message('debug', "Input Class Initialized");

    $CFG =& load_class('Config');
    $this->use_xss_clean	= ($CFG->item('global_xss_filtering') === TRUE) ? TRUE : FALSE;
    $this->allow_get_array	= ($CFG->item('enable_query_strings') === TRUE) ? TRUE : FALSE;
    $this->_sanitize_globals();
  }

  // --------------------------------------------------------------------

  /**
   * Sanitize Globals
   *
   * This function does the following:
   *
   * Unsets $_GET data (if query strings are not enabled)
   *
   * Unsets all globals if register_globals is enabled
   *
   * Standardizes newline characters to \n
   *
   * @access	private
   * @return	void
   */
  function _sanitize_globals() {
  // Would kind of be "wrong" to unset any of these GLOBALS
    $protected = array('_SERVER', '_GET', '_POST', '_FILES', '_REQUEST', '_SESSION', '_ENV', 'GLOBALS', 'HTTP_RAW_POST_DATA',
        'system_folder', 'application_folder', 'BM', 'EXT', 'CFG', 'URI', 'RTR', 'OUT', 'IN');

    // Unset globals for security.
    // This is effectively the same as register_globals = off
    foreach (array($_GET, $_POST, $_COOKIE, $_SERVER, $_FILES, $_ENV, (isset($_SESSION) && is_array($_SESSION)) ? $_SESSION : array()) as $global) {
      if ( ! is_array($global)) {
        if ( ! in_array($global, $protected)) {
          unset($GLOBALS[$global]);
        }
      }
      else {
        foreach ($global as $key => $val) {
          if ( ! in_array($key, $protected)) {
            unset($GLOBALS[$key]);
          }

          if (is_array($val)) {
            foreach($val as $k => $v) {
              if ( ! in_array($k, $protected)) {
                unset($GLOBALS[$k]);
              }
            }
          }
        }
      }
    }

    // Is $_GET data allowed? If not we'll set the $_GET to an empty array
    if ($this->allow_get_array == FALSE) {
      $_GET = array();
    }
    else {
      $_GET = $this->_clean_input_data($_GET);
    }

    // Clean $_POST Data
    $_POST = $this->_clean_input_data($_POST);

    // Clean $_COOKIE Data
    // Also get rid of specially treated cookies that might be set by a server
    // or silly application, that are of no use to a CI application anyway
    // but that when present will trip our 'Disallowed Key Characters' alarm
    // http://www.ietf.org/rfc/rfc2109.txt
    // note that the key names below are single quoted strings, and are not PHP variables
    unset($_COOKIE['$Version']);
    unset($_COOKIE['$Path']);
    unset($_COOKIE['$Domain']);
    $_COOKIE = $this->_clean_input_data($_COOKIE);

    log_message('debug', "Global POST and COOKIE data sanitized");
  }

  // --------------------------------------------------------------------

  /**
   * Clean Input Data
   *
   * This is a helper function. It escapes data and
   * standardizes newline characters to \n
   *
   * @access	private
   * @param	string
   * @return	string
   */
  function _clean_input_data($str) {
    if (is_array($str)) {
      $new_array = array();
      foreach ($str as $key => $val) {
        $new_array[$this->_clean_input_keys($key)] = $this->_clean_input_data($val);
      }
      return $new_array;
    }

    // We strip slashes if magic quotes is on to keep things consistent
    if (get_magic_quotes_gpc()) {
      $str = stripslashes($str);
    }

    // Should we filter the input data?
    if ($this->use_xss_clean === TRUE) {
      $str = $this->xss_clean($str);
    }

    // Standardize newlines
    if (strpos($str, "\r") !== FALSE) {
      $str = str_replace(array("\r\n", "\r"), "\n", $str);
    }

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * Clean Keys
   *
   * This is a helper function. To prevent malicious users
   * from trying to exploit keys we make sure that keys are
   * only named with alpha-numeric text and a few other items.
   *
   * @access	private
   * @param	string
   * @return	string
   */
  function _clean_input_keys($str) {
    if ( ! preg_match("/^[a-z0-9:_\/-]+$/i", $str)) {
      exit('Disallowed Key Characters.');
    }

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * Fetch from array
   *
   * This is a helper function to retrieve values from global arrays
   *
   * @access	private
   * @param	array
   * @param	string
   * @param	bool
   * @return	string
   */
  function _fetch_from_array(&$array, $index = '', $xss_clean = FALSE) {
    if ( ! isset($array[$index])) {
      return FALSE;
    }

    if ($xss_clean === TRUE) {
      return $this->xss_clean($array[$index]);
    }

    return $array[$index];
  }

  // --------------------------------------------------------------------

  /**
   * Fetch an item from the GET array
   *
   * @access	public
   * @param	string
   * @param	bool
   * @return	string
   */
  function get($index = '', $xss_clean = FALSE) {
    return $this->_fetch_from_array($_GET, $index, $xss_clean);
  }

  // --------------------------------------------------------------------

  /**
   * Fetch an item from the POST array
   *
   * @access	public
   * @param	string
   * @param	bool
   * @return	string
   */
  function post($index = '', $xss_clean = FALSE) {
    return $this->_fetch_from_array($_POST, $index, $xss_clean);
  }

  // --------------------------------------------------------------------

  /**
   * Fetch an item from either the GET array or the POST
   *
   * @access	public
   * @param	string	The index key
   * @param	bool	XSS cleaning
   * @return	string
   */
  function get_post($index = '', $xss_clean = FALSE) {
    if ( ! isset($_POST[$index]) ) {
      return $this->get($index, $xss_clean);
    }
    else {
      return $this->post($index, $xss_clean);
    }
  }

  // --------------------------------------------------------------------

  /**
   * Fetch an item from the COOKIE array
   *
   * @access	public
   * @param	string
   * @param	bool
   * @return	string
   */
  function cookie($index = '', $xss_clean = FALSE) {
    return $this->_fetch_from_array($_COOKIE, $index, $xss_clean);
  }

  // --------------------------------------------------------------------

  /**
   * Fetch an item from the SERVER array
   *
   * @access	public
   * @param	string
   * @param	bool
   * @return	string
   */
  function server($index = '', $xss_clean = FALSE) {
    return $this->_fetch_from_array($_SERVER, $index, $xss_clean);
  }

  // --------------------------------------------------------------------

  /**
   * Fetch the IP Address
   *
   * @access	public
   * @return	string
   */
  function ip_address() {
    if ($this->ip_address !== FALSE) {
      return $this->ip_address;
    }

    if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR')) {
      $proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);
      $proxies = is_array($proxies) ? $proxies : array($proxies);

      $this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
    }
    elseif ($this->server('REMOTE_ADDR') AND $this->server('HTTP_CLIENT_IP')) {
      $this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
    }
    elseif ($this->server('REMOTE_ADDR')) {
      $this->ip_address = $_SERVER['REMOTE_ADDR'];
    }
    elseif ($this->server('HTTP_CLIENT_IP')) {
      $this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
    }
    elseif ($this->server('HTTP_X_FORWARDED_FOR')) {
      $this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
    }

    if ($this->ip_address === FALSE) {
      $this->ip_address = '0.0.0.0';
      return $this->ip_address;
    }

    if (strstr($this->ip_address, ',')) {
      $x = explode(',', $this->ip_address);
      $this->ip_address = trim(end($x));
    }

    if ( ! $this->valid_ip($this->ip_address)) {
      $this->ip_address = '0.0.0.0';
    }

    return $this->ip_address;
  }

  // --------------------------------------------------------------------

  /**
   * Validate IP Address
   *
   * Updated version suggested by Geert De Deckere
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function valid_ip($ip) {
    $ip_segments = explode('.', $ip);

    // Always 4 segments needed
    if (count($ip_segments) != 4) {
      return FALSE;
    }
    // IP can not start with 0
    if ($ip_segments[0][0] == '0') {
      return FALSE;
    }
    // Check each segment
    foreach ($ip_segments as $segment) {
    // IP segments must be digits and can not be
    // longer than 3 digits or greater then 255
      if ($segment == '' OR preg_match("/[^0-9]/", $segment) OR $segment > 255 OR strlen($segment) > 3) {
        return FALSE;
      }
    }

    return TRUE;
  }

  // --------------------------------------------------------------------

  /**
   * User Agent
   *
   * @access	public
   * @return	string
   */
  function user_agent() {
    if ($this->user_agent !== FALSE) {
      return $this->user_agent;
    }

    $this->user_agent = ( ! isset($_SERVER['HTTP_USER_AGENT'])) ? FALSE : $_SERVER['HTTP_USER_AGENT'];

    return $this->user_agent;
  }

  // --------------------------------------------------------------------

  /**
   * Filename Security
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function filename_security($str) {
    $bad = array(
        "../",
        "./",
        "<!--",
        "-->",
        "<",
        ">",
        "'",
        '"',
        '&',
        '$',
        '#',
        '{',
        '}',
        '[',
        ']',
        '=',
        ';',
        '?',
        "%20",
        "%22",
        "%3c",		// <
        "%253c", 	// <
        "%3e", 		// >
        "%0e", 		// >
        "%28", 		// (
        "%29", 		// )
        "%2528", 	// (
        "%26", 		// &
        "%24", 		// $
        "%3f", 		// ?
        "%3b", 		// ;
        "%3d"		// =
    );

    return stripslashes(str_replace($bad, '', $str));
  }

  // --------------------------------------------------------------------

  /**
   * XSS Clean
   *
   * Sanitizes data so that Cross Site Scripting Hacks can be
   * prevented.  This function does a fair amount of work but
   * it is extremely thorough, designed to prevent even the
   * most obscure XSS attempts.  Nothing is ever 100% foolproof,
   * of course, but I haven't been able to get anything passed
   * the filter.
   *
   * Note: This function should only be used to deal with data
   * upon submission.  It's not something that should
   * be used for general runtime processing.
   *
   * This function was based in part on some code and ideas I
   * got from Bitflux: http://blog.bitflux.ch/wiki/XSS_Prevention
   *
   * To help develop this script I used this great list of
   * vulnerabilities along with a few other hacks I've
   * harvested from examining vulnerabilities in other programs:
   * http://ha.ckers.org/xss.html
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function xss_clean($str, $is_image = FALSE) {
										  /*
										   * Is the string an array?
										   *
										   */
    if (is_array($str)) {
      while (list($key) = each($str)) {
        $str[$key] = $this->xss_clean($str[$key]);
      }

      return $str;
    }

										  /*
										   * Remove Invisible Characters
										   */
    $str = $this->_remove_invisible_characters($str);

										  /*
										   * Protect GET variables in URLs
										   */

    // 901119URL5918AMP18930PROTECT8198

    $str = preg_replace('|\&([a-z\_0-9]+)\=([a-z\_0-9]+)|i', $this->xss_hash()."\\1=\\2", $str);

										  /*
										   * Validate standard character entities
										   *
										   * Add a semicolon if missing.  We do this to enable
										   * the conversion of entities to ASCII later.
										   *
										   */
    $str = preg_replace('#(&\#?[0-9a-z]{2,})([\x00-\x20])*;?#i', "\\1;\\2", $str);

										  /*
										   * Validate UTF16 two byte encoding (x00)
										   *
										   * Just as above, adds a semicolon if missing.
										   *
										   */
    $str = preg_replace('#(&\#x?)([0-9A-F]+);?#i',"\\1\\2;",$str);

										  /*
										   * Un-Protect GET variables in URLs
										   */
    $str = str_replace($this->xss_hash(), '&', $str);

										  /*
										   * URL Decode
										   *
										   * Just in case stuff like this is submitted:
										   *
										   * <a href="http://%77%77%77%2E%67%6F%6F%67%6C%65%2E%63%6F%6D">Google</a>
										   *
										   * Note: Use rawurldecode() so it does not remove plus signs
										   *
										   */
    $str = rawurldecode($str);

										  /*
										   * Convert character entities to ASCII
										   *
										   * This permits our tests below to work reliably.
										   * We only convert entities that are within tags since
										   * these are the ones that will pose security problems.
										   *
										   */

    $str = preg_replace_callback("/[a-z]+=([\'\"]).*?\\1/si", array($this, '_convert_attribute'), $str);

    $str = preg_replace_callback("/<\w+.*?(?=>|<|$)/si", array($this, '_html_entity_decode_callback'), $str);

										  /*
										   * Remove Invisible Characters Again!
										   */
    $str = $this->_remove_invisible_characters($str);

										  /*
										   * Convert all tabs to spaces
										   *
										   * This prevents strings like this: ja	vascript
										   * NOTE: we deal with spaces between characters later.
										   * NOTE: preg_replace was found to be amazingly slow here on large blocks of data,
										   * so we use str_replace.
										   *
										   */

    if (strpos($str, "\t") !== FALSE) {
      $str = str_replace("\t", ' ', $str);
    }

										  /*
										   * Capture converted string for later comparison
										   */
    $converted_string = $str;

										  /*
										   * Not Allowed Under Any Conditions
										   */

    foreach ($this->never_allowed_str as $key => $val) {
      $str = str_replace($key, $val, $str);
    }

    foreach ($this->never_allowed_regex as $key => $val) {
      $str = preg_replace("#".$key."#i", $val, $str);
    }

										  /*
										   * Makes PHP tags safe
										   *
										   *  Note: XML tags are inadvertently replaced too:
										   *
										   *	<?xml
										   *
										   * But it doesn't seem to pose a problem.
										   *
										   */
    if ($is_image === TRUE) {
    // Images have a tendency to have the PHP short opening and closing tags every so often
    // so we skip those and only do the long opening tags.
      $str = preg_replace('/<\?(php)/i', "&lt;?\\1", $str);
    }
    else {
      $str = str_replace(array('<?', '?'.'>'),  array('&lt;?', '?&gt;'), $str);
    }

										  /*
										   * Compact any exploded words
										   *
										   * This corrects words like:  j a v a s c r i p t
										   * These words are compacted back to their correct state.
										   *
										   */
    $words = array('javascript', 'expression', 'vbscript', 'script', 'applet', 'alert', 'document', 'write', 'cookie', 'window');
    foreach ($words as $word) {
      $temp = '';

      for ($i = 0, $wordlen = strlen($word); $i < $wordlen; $i++) {
        $temp .= substr($word, $i, 1)."\s*";
      }

      // We only want to do this when it is followed by a non-word character
      // That way valid stuff like "dealer to" does not become "dealerto"
      $str = preg_replace_callback('#('.substr($temp, 0, -3).')(\W)#is', array($this, '_compact_exploded_words'), $str);
    }

										  /*
										   * Remove disallowed Javascript in links or img tags
										   * We used to do some version comparisons and use of stripos for PHP5, but it is dog slow compared
										   * to these simplified non-capturing preg_match(), especially if the pattern exists in the string
										   */
    do {
      $original = $str;

      if (preg_match("/<a/i", $str)) {
        $str = preg_replace_callback("#<a\s+([^>]*?)(>|$)#si", array($this, '_js_link_removal'), $str);
      }

      if (preg_match("/<img/i", $str)) {
        $str = preg_replace_callback("#<img\s+([^>]*?)(\s?/?>|$)#si", array($this, '_js_img_removal'), $str);
      }

      if (preg_match("/script/i", $str) OR preg_match("/xss/i", $str)) {
        $str = preg_replace("#<(/*)(script|xss)(.*?)\>#si", '[removed]', $str);
      }
    }
    while($original != $str);

    unset($original);

										  /*
										   * Remove JavaScript Event Handlers
										   *
										   * Note: This code is a little blunt.  It removes
										   * the event handler and anything up to the closing >,
										   * but it's unlikely to be a problem.
										   *
										   */
    $event_handlers = array('[^a-z_\-]on\w*','xmlns');

    if ($is_image === TRUE) {
										    /*
										     * Adobe Photoshop puts XML metadata into JFIF images, including namespacing,
										     * so we have to allow this for images. -Paul
										     */
      unset($event_handlers[array_search('xmlns', $event_handlers)]);
    }

    $str = preg_replace("#<([^><]+?)(".implode('|', $event_handlers).")(\s*=\s*[^><]*)([><]*)#i", "<\\1\\4", $str);

										  /*
										   * Sanitize naughty HTML elements
										   *
										   * If a tag containing any of the words in the list
										   * below is found, the tag gets converted to entities.
										   *
										   * So this: <blink>
										   * Becomes: &lt;blink&gt;
										   *
										   */
    $naughty = 'alert|applet|audio|basefont|base|behavior|bgsound|blink|body|embed|expression|form|frameset|frame|head|html|ilayer|iframe|input|isindex|layer|link|meta|object|plaintext|style|script|textarea|title|video|xml|xss';
    $str = preg_replace_callback('#<(/*\s*)('.$naughty.')([^><]*)([><]*)#is', array($this, '_sanitize_naughty_html'), $str);

										  /*
										   * Sanitize naughty scripting elements
										   *
										   * Similar to above, only instead of looking for
										   * tags it looks for PHP and JavaScript commands
										   * that are disallowed.  Rather than removing the
										   * code, it simply converts the parenthesis to entities
										   * rendering the code un-executable.
										   *
										   * For example:	eval('some code')
										   * Becomes:		eval&#40;'some code'&#41;
										   *
										   */
    $str = preg_replace('#(alert|cmd|passthru|eval|exec|expression|system|fopen|fsockopen|file|file_get_contents|readfile|unlink)(\s*)\((.*?)\)#si', "\\1\\2&#40;\\3&#41;", $str);

										  /*
										   * Final clean up
										   *
										   * This adds a bit of extra precaution in case
										   * something got through the above filters
										   *
										   */
    foreach ($this->never_allowed_str as $key => $val) {
      $str = str_replace($key, $val, $str);
    }

    foreach ($this->never_allowed_regex as $key => $val) {
      $str = preg_replace("#".$key."#i", $val, $str);
    }

										  /*
										   *  Images are Handled in a Special Way
										   *  - Essentially, we want to know that after all of the character conversion is done whether
										   *  any unwanted, likely XSS, code was found.  If not, we return TRUE, as the image is clean.
										   *  However, if the string post-conversion does not matched the string post-removal of XSS,
										   *  then it fails, as there was unwanted XSS code found and removed/changed during processing.
										   */

    if ($is_image === TRUE) {
      if ($str == $converted_string) {
        return TRUE;
      }
      else {
        return FALSE;
      }
    }

    log_message('debug', "XSS Filtering completed");
    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * Random Hash for protecting URLs
   *
   * @access	public
   * @return	string
   */
  function xss_hash() {
    if ($this->xss_hash == '') {
      if (phpversion() >= 4.2)
        mt_srand();
      else
        mt_srand(hexdec(substr(md5(microtime()), -8)) & 0x7fffffff);

      $this->xss_hash = md5(time() + mt_rand(0, 1999999999));
    }

    return $this->xss_hash;
  }

  // --------------------------------------------------------------------

  /**
   * Remove Invisible Characters
   *
   * This prevents sandwiching null characters
   * between ascii characters, like Java\0script.
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function _remove_invisible_characters($str) {
    static $non_displayables;

    if ( ! isset($non_displayables)) {
    // every control character except newline (dec 10), carriage return (dec 13), and horizontal tab (dec 09),
      $non_displayables = array(
          '/%0[0-8bcef]/',			// url encoded 00-08, 11, 12, 14, 15
          '/%1[0-9a-f]/',				// url encoded 16-31
          '/[\x00-\x08]/',			// 00-08
          '/\x0b/', '/\x0c/',			// 11, 12
          '/[\x0e-\x1f]/'				// 14-31
      );
    }

    do {
      $cleaned = $str;
      $str = preg_replace($non_displayables, '', $str);
    }
    while ($cleaned != $str);

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * Compact Exploded Words
   *
   * Callback function for xss_clean() to remove whitespace from
   * things like j a v a s c r i p t
   *
   * @access	public
   * @param	type
   * @return	type
   */
  function _compact_exploded_words($matches) {
    return preg_replace('/\s+/s', '', $matches[1]).$matches[2];
  }

  // --------------------------------------------------------------------

  /**
   * Sanitize Naughty HTML
   *
   * Callback function for xss_clean() to remove naughty HTML elements
   *
   * @access	private
   * @param	array
   * @return	string
   */
  function _sanitize_naughty_html($matches) {
  // encode opening brace
    $str = '&lt;'.$matches[1].$matches[2].$matches[3];

    // encode captured opening or closing brace to prevent recursive vectors
    $str .= str_replace(array('>', '<'), array('&gt;', '&lt;'), $matches[4]);

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * JS Link Removal
   *
   * Callback function for xss_clean() to sanitize links
   * This limits the PCRE backtracks, making it more performance friendly
   * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
   * PHP 5.2+ on link-heavy strings
   *
   * @access	private
   * @param	array
   * @return	string
   */
  function _js_link_removal($match) {
    $attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
    return str_replace($match[1], preg_replace("#href=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
  }

  /**
   * JS Image Removal
   *
   * Callback function for xss_clean() to sanitize image tags
   * This limits the PCRE backtracks, making it more performance friendly
   * and prevents PREG_BACKTRACK_LIMIT_ERROR from being triggered in
   * PHP 5.2+ on image tag heavy strings
   *
   * @access	private
   * @param	array
   * @return	string
   */
  function _js_img_removal($match) {
    $attributes = $this->_filter_attributes(str_replace(array('<', '>'), '', $match[1]));
    return str_replace($match[1], preg_replace("#src=.*?(alert\(|alert&\#40;|javascript\:|charset\=|window\.|document\.|\.cookie|<script|<xss|base64\s*,)#si", "", $attributes), $match[0]);
  }

  // --------------------------------------------------------------------

  /**
   * Attribute Conversion
   *
   * Used as a callback for XSS Clean
   *
   * @access	public
   * @param	array
   * @return	string
   */
  function _convert_attribute($match) {
    return str_replace(array('>', '<', '\\'), array('&gt;', '&lt;', '\\\\'), $match[0]);
  }

  // --------------------------------------------------------------------

  /**
   * HTML Entity Decode Callback
   *
   * Used as a callback for XSS Clean
   *
   * @access	public
   * @param	array
   * @return	string
   */
  function _html_entity_decode_callback($match) {
    $CFG =& load_class('Config');
    $charset = $CFG->item('charset');

    return $this->_html_entity_decode($match[0], strtoupper($charset));
  }

  // --------------------------------------------------------------------

  /**
   * HTML Entities Decode
   *
   * This function is a replacement for html_entity_decode()
   *
   * In some versions of PHP the native function does not work
   * when UTF-8 is the specified character set, so this gives us
   * a work-around.  More info here:
   * http://bugs.php.net/bug.php?id=25670
   *
   * @access	private
   * @param	string
   * @param	string
   * @return	string
   */
										/* -------------------------------------------------
										 /*  Replacement for html_entity_decode()
										 /* -------------------------------------------------*/

										/*
										 NOTE: html_entity_decode() has a bug in some PHP versions when UTF-8 is the
										 character set, and the PHP developers said they were not back porting the
										 fix to versions other than PHP 5.x.
										 */
  function _html_entity_decode($str, $charset='UTF-8') {
    if (stristr($str, '&') === FALSE) return $str;

    // The reason we are not using html_entity_decode() by itself is because
    // while it is not technically correct to leave out the semicolon
    // at the end of an entity most browsers will still interpret the entity
    // correctly.  html_entity_decode() does not convert entities without
    // semicolons, so we are left with our own little solution here. Bummer.

    if (function_exists('html_entity_decode') && (strtolower($charset) != 'utf-8' OR version_compare(phpversion(), '5.0.0', '>='))) {
      $str = html_entity_decode($str, ENT_COMPAT, $charset);
      $str = preg_replace('~&#x(0*[0-9a-f]{2,5})~ei', 'chr(hexdec("\\1"))', $str);
      return preg_replace('~&#([0-9]{2,4})~e', 'chr(\\1)', $str);
    }

    // Numeric Entities
    $str = preg_replace('~&#x(0*[0-9a-f]{2,5});{0,1}~ei', 'chr(hexdec("\\1"))', $str);
    $str = preg_replace('~&#([0-9]{2,4});{0,1}~e', 'chr(\\1)', $str);

    // Literal Entities - Slightly slow so we do another check
    if (stristr($str, '&') === FALSE) {
      $str = strtr($str, array_flip(get_html_translation_table(HTML_ENTITIES)));
    }

    return $str;
  }

  // --------------------------------------------------------------------

  /**
   * Filter Attributes
   *
   * Filters tag attributes for consistency and safety
   *
   * @access	public
   * @param	string
   * @return	string
   */
  function _filter_attributes($str) {
    $out = '';

    if (preg_match_all('#\s*[a-z\-]+\s*=\s*(\042|\047)([^\\1]*?)\\1#is', $str, $matches)) {
      foreach ($matches[0] as $match) {
        $out .= preg_replace("#/\*.*?\*/#s", '', $match);
      }
    }

    return $out;
  }

// --------------------------------------------------------------------

}
// END Input class

/* End of file Input.php */
/* Location: ./system/libraries/Input.php */